Eight years ago today, George W. Bush was took the oath as the 43rd president.
"It's when the president takes the oath of office that they recognize the burden is real," says Andrew Card, President Bush's former chief of staff. "It can't be shared with anybody else."
Card was President Bush's first chief of staff, and was with him at the moment he took office.
"He said, 'It's done, and I didn't realize it would be as awesome as it was, and the obligation would be as great as I feel,'" Card remembers.
In an instant, the new president is in charge, gaining control of firing codes for an arsenal of nuclear weapons.
"The military aide to the president will brief the president right after he's taken the oath," says Card.
This afternoon is when the real business begins.
"He'll walk in the Oval Office, and there will be a moment when the responsibilities of the president land squarely on his shoulders," Mr. Bush said at a recent news conference.
"Nobody can really prepare someone to assume the presidency," says Alan Lichtman, a presidential historian at American University. "And nobody can really prepare to stop being president. By his own account, President Bush is ready to return to private life. But still ..."
"From being the toast of the world, from traveling around in Air Force 1, from being possibly the most powerful person on the globe, you go to private citizen," adds Lichtman.
Send your pictures, videos and e-mails on Inauguration Day activities to Natali del Conte Tuesday morning, at firstname.lastname@example.org.
If you're on Twitter, you can "tweet" us at Twitter.com/theearlyshow.
To see the CBSNews.com Special Report: Inauguration '09," click here.